Field of the Invention
The present invention relates to an image stabilization apparatus and a method of controlling an image stabilization apparatus.
Description of the Related Art
There are cases where camera shake brought on by movement of the hands of a user holding a camera body leads to blurring (camera shake) of a subject when shooting an image with an image capturing apparatus such as a digital camera, and an image capturing apparatus that includes an image stabilization system that corrects camera shake has been proposed.
Conventionally, an optical image stabilization process or an electrical image stabilization process has been used as the correction process by the image stabilization system. In a general optical image stabilization process, vibrations applied to a camera body are detected by an angular velocity sensor or the like, and a camera shake correction lens that is provided in an imaging optical system is shifted in a direction perpendicular to the optical axis in accordance with the detection results. Accordingly, the camera shake is corrected by shifting the path of the entering light so as to shift the image that has formed on a light receiving surface of an image sensor. On the other hand, in a general electrical image stabilization process, the camera shake is virtually corrected by changing a cut-out range of the captured image.
As an imaging lens that includes a conventional camera shake correction unit, Japanese Patent Laid-Open No. 2001-249276 proposes an imaging lens that corrects camera shake by shifting multiple correction lenses in a direction that is different from an optical axis.
It is disclosed in Japanese Patent Laid-Open No. 2001-249276 that, in the imaging lens that has an image stabilization function, either a correction lens group that is made up of multiple correction lenses is shifted integrally in a direction that is different from the optical axis direction, or the correction lens group is integrally rotated with the vicinity of the center of gravity of the stabilization lens group as the center. Accordingly, in comparison to the case where image stabilization is performed with a single correction lens, the shifting amount of an image with respect to the driving amount of the stabilization lens group is increased, and the deterioration of optical properties (mainly eccentric aberration) that occurs when the correction lens group is shifted is suppressed to a low level. Also, it is disclosed that an increase in size of the apparatus is suppressed by using the same drive mechanism to integrally perform driving of the stabilization lens group.
However, in the case where the stabilization lens group is integrally driven by the same driving apparatus as in Japanese Patent Laid-Open No. 2001-249276, the lenses are always driven in synchronization, and therefore in scenes with large camera shake such as moving image shooting while walking, the multiple lenses simultaneously reach the limit of the scope in which camera shake correction is possible. Accordingly, there is a possibility of deterioration in image stabilization performance.